Abstract
Additive manufacturing and the welding of copper materials are expected in various industries since
their properties, including thermal and electrical conductivities, outperform other metals. An infrared
(IR) laser is usually used for laser additive manufacturing and welding. However, it is difficult to
perform additive manufacturing and copper welding because copper has high reflectivity at the IR laser
wavelength. The copper absorptivity is increased as the light wavelength is decreased. In the
wavelength range of 400 to 460 nm blue light, the extra comma really makes this sentence confusing.
Isn’t this what you mean? The copper absorptance is much higher than that in the wavelength range of
IR light. Therefore, a high-power blue diode laser is required. A 100 W blue diode laser has been
developed using semiconductor laser devices with a 450 nm wavelength in a project promoted by
NEDO. The blue diode laser has already been installed in a thermal welding system.
